The measurement of the doping profile of semiconductor devices is useful in determining junction depths (dopant density), which in turn, are useful for the design process. For example, transistor design is based on modeling and/or mathematical equations. These equations are based on physical properties, such as junction depth (dopant density), or behavior.
One method of determining the junction depth of the device, junction staining for one dimensional analysis was typically done. The junction staining involved angle lapping and then staining the junction and measuring. The staining process comprises applying a chemical etchant which will preferentially attack n+doped material or p+doped material, allowing the technician to delineate the location of the junction and measure its depth. Two dimensional junction depth measurement is necessary when submicron features are being formed, because many two dimensional electric field effects need to be accounted for. Various prior art chemical staining and Auger spectroscopy techniques have been used, but have drawbacks. For example, many known methods have feature-size limits, and others involve destructive measurements.
What is needed, therefore, is a method and apparatus for measuring doping profiles that overcomes at least the drawbacks of known devices and methods described above.